Cardiopulmonary resuscitation (CPR) is a well-known and valuable method of first aid used to resuscitate people who have suffered from cardiac arrest. CPR requires repetitive chest compressions to squeeze the heart and the thoracic cavity to pump blood through the body. Artificial respiration, such as mouth-to-mouth breathing or bag mask respiration, is used to supply air to the lungs. When a first aid provider performs manual chest compression effectively, blood flow in the body is about 25% to 30% of normal blood flow.
In efforts to provide better blood flow and increase the effectiveness of bystander resuscitation efforts, various mechanical devices have been proposed for performing CPR. Among the variations are pneumatic vests, hydraulic and electric piston devices as well as manual and automatic belt drive chest compression devices.
Piston-based chest compression systems are illustrated in Nilsson, et al., CPR Device and Method, U.S. Patent Publication 2010/0185127 (Jul. 22, 2010), Sebelius, et al., Support Structure, U.S. Patent Publication 2009/0260637 (Oct. 22, 2009), Sebelius, et al., Rigid Support Structure on Two Legs for CPR, U.S. Pat. No. 7,569,021 (Aug. 4, 2009), Steen, Systems and Procedures for Treating Cardiac Arrest, U.S. Pat. No. 7,226,427 (Jun. 5, 2007) and King, Gas-Driven Chest Compression Device, U.S. Patent Publication 2010/0004572 (Jan. 7, 2010) all of which are hereby incorporated by reference.
Our own patents, Mollenauer et al., Resuscitation device having a motor driven belt to constrict/compress the chest, U.S. Pat. No. 6,142,962 (Nov. 7, 2000); Sherman, et al., CPR Assist Device with Pressure Bladder Feedback, U.S. Pat. No. 6,616,620 (Sep. 9, 2003); Sherman et al., Modular CPR assist device, U.S. Pat. No. 6,066,106 (May 23, 2000); and Sherman et al., Modular CPR assist device, U.S. Pat. No. 6,398,745 (Jun. 4, 2002), and Escudero, et al., Compression Belt System for Use with Chest Compression Devices, U.S. Pat. No. 7,410,470 (Aug. 12, 2008), show chest compression devices that compress a patient's chest with a belt. Our commercial device, sold under the trademark AUTOPULSE®, is described in some detail in our prior patents, including Jensen, Lightweight Electro-Mechanical Chest Compression Device, U.S. Pat. No. 7,347,832 (Mar. 25, 2008) and Quintana, et al., Methods and Devices for Attaching a Belt Cartridge to a Chest Compression Device, U.S. Pat. No. 7,354,407 (Apr. 8, 2008).
As mechanical compressions are performed by piston-based chest compression systems, the patient's rib cage hinges or shifts about the sternum resulting in lateral spreading of the thorax and the effectiveness of the automated chest compressions are diminished. The repeated extension and retraction of the piston often results in the piston and compression cup moving or “walking” up the patient's chest toward the neck or moving down toward the patient's abdomen.